The CoRoT satellite permits observation of the infinite gradations of luminosity on the surface of stars, with a precision hitherto unknown. Kevin Belkacem and his colleagues have discovered a new class of stars, massive stars that exhibit surface oscillations that are oddly similar to those shown by our own sun (1).

The space mission CoRoT (COnvection ROtation and planetary Transits) was launched on December 27, 2006. It was developed and is being used by the CNES, with contributions from Germany, Austria, Belgium, Brazil, Spain and the European Space Agency (Read the article Voyage to the Centre of the Stars). It has two purposes: to observe planets orbiting around stars other than the sun, and to observe oscillations that occur on the surface of those stars. Observational astroseismology, also called stellar seismology, is a unique study that attempts to make inferences about vibrations that perturb stars’ surfaces at all times, and which are indicated by tiny and periodic variations in luminosity.

The principles of astroseismology are the same as those employed in terrestrial seismology, which enable us to learn about the interior of the earth through the study of vibratory frequencies that occur during earthquakes. A star can be thought of as a beating heart, whose rhythms come from its interior. Methods called “inversion methods” and other theoretical models allow inferences to be drawn from surface oscillations, and these provide clues about the fluid dynamics at work in the interior of a star. This information about the physics of the interior of a star provides possible answers to such questions as: how do stars change? How old are they? Nearer to home, the physics of stars could allow us to predict solar storms, which cause significant damage on earth and affect our daily lives.

Stars’ surfaces are constantly vibrating, and the study of these vibrations is important for stellar physics... Even if stars are the basic building blocks of the structure of the Universe, their interior makeup remains unknown, and theoretical models remain just that, theoretical, except as regards our sun.

(1) Belkacem K., Samadi R., Goupil M.J., Lefèvre L., Baudin F., Deheuvels S., Dupret M.A., Appourchaux T., Scuflaire R., Auvergne M., Catala C., Michel E., Miglio A., Montalban J., Thoul A., Talon S., Baglin A., Noels A. Solar-like oscillations in a massive star, Science